滇黔桂矿集区微细浸染型金矿成矿年代学研究

近10多年来,许多研究者对滇黔桂矿集区微细浸染型金矿成矿年代学进行了研究,采用的同位素定年方法有蚀变矿物及流体包裹体Rb-Sr法,硫化物Pb-Pb法,石英裂变径迹法等,获得了276~259、206、157~82 Ma等3组数据.文中对这些测年方法及所获数据进行了分析和比较,初步探讨了这些测年数据与右江盆地发展演化历史和相关的构造-热事件的关系,认为伴随盆地裂解的二叠纪玄武岩岩浆活动主要起提供部分矿源层的作用,而110~80 Ma华南岩石圈大规模伸展及相关岩浆活动可能是该区大规模成矿的动力学背景.提出了利用硫化物Re-Os法,热液绢云母40Ar-39Ar法等直接精确测定热液矿物年龄以获得成矿年龄的方法和可能途径.

A review on the chronology of micro-disseminated gold deposits in Yunnan-Guizhou-Guangxi triangle area, southwestern China

Many researchers have studied the chronology on the micro-disseminated gold deposits in Yunnan-Guizhou-Guangxi triangle area in southwest China in the past ten years.Reported dating methods comprise Rb-Sr dating on alteration minerals and fluid inclusions,Pb-Pb dating of sulphide,and fission-track dating of quartz.The ages reported range from 276 Ma to as young as 82 Ma,and fall into three groups,i.e.276~259 Ma,206 Ma,and 157~82 Ma.Dating methods and ages reported are analyzecl and compared.The relationship between these ages reported and corresponding tectonic-thermal events are discusseol in this paper.It is considered that Permian basalt erupted during the development of the Youjiang Late Paleozoic basin providing partly Au,and that large scale lithospheric extension and related magmatic activity in 110~80 Ma in south China are the dynamic setting for the large scale metallogenesis of micro-disseminated gold deposits in Yunnan-Guizhou-Guangxi triangle area,part of the south China metallogenic province.The high precision dating methods,such as,Re-Os dating of sulphide and ~(40)Ar-~(39)Ar dating of sericites are proposed to date this type of gold deposits.